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A259193 5x + 1 sequence beginning at 11. 1
11, 56, 28, 14, 7, 36, 18, 9, 46, 23, 116, 58, 29, 146, 73, 366, 183, 916, 458, 229, 1146, 573, 2866, 1433, 7166, 3583, 17916, 8958, 4479, 22396, 11198, 5599, 27996, 13998, 6999, 34996, 17498, 8749, 43746, 21873, 109366, 54683, 273416, 136708, 68354, 34177, 170886, 85443 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Alonso del Arte, Table of n, a(n) for n = 0..999

Alex V. Kontorovich & Jeffrey C. Lagarias, Stochastic Models for the 3x+1 and 5x+1 Problems arXiv:0910.1944 [math.NT], 2009.

FORMULA

a(0) = 11; a(n) = 5a(n - 1) + 1 if a(n - 1) is odd, a(n) = a(n - 1)/2 otherwise.

EXAMPLE

11 is odd, so it's followed by 5 * 11 + 1 = 56.

56 is even, so it's followed by 56/2 = 28.

MATHEMATICA

NestList[If[EvenQ[#], #/2, 5# + 1] &, 5, 100]

PROG

(MAGMA) [n eq 1 select 11 else IsOdd(Self(n-1)) select 5*Self(n-1)+1 else Self(n-1) div 2: n in [1..80]]; // Vincenzo Librandi, Jul 04 2015

CROSSREFS

Cf. A259207, A057688.

Sequence in context: A032166 A218000 A206528 * A099532 A041226 A042503

Adjacent sequences:  A259190 A259191 A259192 * A259194 A259195 A259196

KEYWORD

nonn,easy

AUTHOR

Alonso del Arte, Jun 21 2015

STATUS

approved

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Last modified November 16 21:37 EST 2018. Contains 317275 sequences. (Running on oeis4.)